function draw_gray_grid(x_vals, y_vals)

    
    

    %y_vals = linspace(0, 1, 11);
    
    x_hor = [x_vals(1) x_vals(size(x_vals,2))];
    y_hor = [y_vals(size(y_vals, 2)) y_vals(size(y_vals, 2))];
    %plot(x_hor, y_hor, 'k');

    grey = [0.7,0.7,0.7];

    for iii = 2:size(y_vals,2)-1
        y_hor = [y_vals(iii) y_vals(iii)];
        plot(x_hor, y_hor, 'Color', grey, 'LineWidth', 0.2, 'LineStyle', '--');
    end

    %x_vals = linspace(0, maxFeatures, 6);

    x_ver = [x_vals(size(x_vals, 2)) x_vals(size(x_vals, 2))];
    y_ver = [y_vals(1) y_vals(size(y_vals, 2))];
    %plot(x_ver, y_ver, 'k');

    grey = [0.7,0.7,0.7];

    for iii = 2:size(x_vals,2)-1
        x_ver = [x_vals(iii) x_vals(iii)];
        y_ver;
        plot(x_ver, y_ver, 'Color', grey, 'LineWidth', 0.2, 'LineStyle', '--');
    end

    %axis([x_hor y_ver]);

     xlhand = get(gca,'xlabel');
    set(xlhand,'fontsize',16);
    ylhand = get(gca,'ylabel');
    set(ylhand,'fontsize',16);
    
    box on
    
    %set(gca,'XTick',[],'YTick',[])

    %G = gca;
    %set(G,'gridlinestyle','-');
end